Williams needed nearly two hours to advance and next plays third-seeded Petra Kvitova, runner-up to Naomi Osaka at the Australian Open in January. Williams' younger sister, Serena, received a first-round bye and will play Victoria Azarenka in a rematch of the 2016 final in the Southern California desert. Azarenka won that year, the last time the two major champions met.
Other women's winners were Americans Madison Brengle and Christina McHale, Kristina Mladenovic, Kirsten Flipkens, Monica Puig and Yulia Putintseva. Taylor Townsend lost to Ysaline Bonaventure 6-7 (3), 7-5, 6-2.
Men's play began Thursday, with Philipp Kohlschreiber defeating Pierre-Hugues Hebert 6-4, 6-0. Americans Sam Querrey, Bjorn Fratangelo and Marcos Giron also advanced.
More AP Tennis: https://www.apnews.com/apf-Tennis and https://twitter.com/AP_Sports